Nature Trail
Gharials are no man-eaters
Remember the fearsome looking members of the reptile family we
introduced to you recently? Well, today we thought of bringing more
information about one of these creatures, which though not such a
pleasant animal to look at, is rather fascinating, simply because of its
long snout. The gharial which is sometimes called the Indian gavial or
gavial, is one of two surviving members of the family Gavialidae, a
long-established group of crocodile-like reptiles with long, narrow
jaws.
If you have never seen a creature like this in our country do not be
surprised because it is found mostly in neighbouring India and
Nepal.They may be seen in our country too and some refer to them as the
hala kimbula.
In fact it is one of the three crocodilians found in India, the
others being the Mugger crocodile and the Saltwater crocodile. It is a
critically endangered species, Gharials once thrived in all the major
river systems of the Indian subcontinent, spanning the rivers of its
northern part from the Indus in Pakistan Gangetic floodplain to the
Irrawaddy in Myanmar. Today however, their distribution is limited to
only two per cent of their former range.
The shape of the characteristic elongated, narrow snout, similar only
to the closely related False gharial, (Tomistoma schlegelii) varies with
the age of the saurian. The snout becomes progressively thinner, the
older the gharial gets. The bulbous (bulb shape) growth on the tip of
the male’s snout is called a ‘ghara’ after the Indian word meaning
‘pot’. It is present in mature individuals. The ghara is used to
generate a resonant hum during vocalisation and acts as a visual lure
for attracting females. It is also used to make bubbles which have been
associated with the mating rituals of the species. The elongated jaws
are lined with many interlocking, razor-sharp teeth - an adaptation to
the diet (predominantly fish in adults).
There are 27 to 29 upper and 25 or 26 lower teeth on each side. These
teeth are not received into interdental pits; the first, second, and
third mandibular teeth fit into notches in the upper jaw. The front
teeth are the largest.
Young gharials eat insects, larvae, and small frogs. Mature adults
feed almost solely on fish, although some individuals have been known to
scavenge dead animals. Their numerous needle-like teeth are ideal for
holding on to struggling, slippery fish. Gharials will often use their
body to corral (enclose) fish against the bank where they can be more
easily snapped up. This species is one of the largest of all crocodilian
species, being the only crocodilian besides the Saltwater Crocodile (Crocodylus
porosus) and Nile crocodile (Crocodylus niloticus) with multiple records
of attaining a length of six metres (20 feet) and a weight of 1000 kg
(2200 lbs). However, a majority of gharials do not grow past five metres
(16.5 feet) and about 680 kg (1500 lbs). The average size of mature
gharials is 3.6-4.5 m (12.2-15.5 ft) about the same as for male
Saltwater Crocodiles and Nile Crocodiles.
The physical attributes of the gharial do not make it very suited for
moving about on land. In fact the only reasons the gharial leaves the
water is either to bask in the sun or to nest on the sandbanks of the
river.
The leg musculature of the gharial does not enable it to raise its
body off the ground (on land) to achieve the high-walk gait’ and is able
only to push its body forward across the ground (‘belly-sliding’),
although it can do this with some speed when required. However, when in
water, the gharial is the most nimble and quick of all the crocodilians
in the world.
The tail seems overdeveloped and is laterally flattened, more so than
other crocodilians, which enables it to achieve excellent aquatic
locomotive abilities. The outer toes of a gharial are two-thirds webbed,
while the middle toe is only one-third webbed. Gharials have a strong
crest on the outer edge of the forearm, leg, and foot. Typically, adult
gharials consist of a dark olive colour tone while young ones are pale
olive, with dark brown spots or cross-bands. If ever you come across a
gharial you need not be afraid of being eaten up by it because the
animal is not a man-eater.It is sensitive towards humans.And despite its
immense size, its thin and fragile jaws make it physically incapable and
impossible for the gharial to consume a large animal, especially a human
being. The myth that gharials eat humans may be partly due to the fact
that they are similar in appearance to crocodiles and also since
jewellery has been found in their stomachs.
However, the gharial may have swallowed this jewelry while scavenging
corpses or as gastroliths used to aid digestion or buoyancy management.
The nesting and laying of eggs takes place in the dry season of March,
April, and May because during the dry season, the rivers shrink a bit
and the sandy river banks are available for nesting. The gharial mum
deposits between 30 and 50 eggs into the hole that she digs up before it
is covered over carefully. After about 90 days, the babies emerge.
However, there is no record of the female assisting the young into the
water after they hatch. This may probably be because their jaws are not
suited for carrying the young due to the needle like teeth.But the
mother does protect the young in the water for a few days until they
learn to fend for themselves.
Fact and pix: Internet
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Fact file
* The most distinctive feature of the group is the very long, narrow
snout, which is an adaptation to a diet of small fish.
* The earliest gharial may have been related to the modern types:
some died out at the same time as the dinosaurs (at the end of the
Cretaceous), others survived until the early Eocene. The modern forms
appeared at much the same time, evolving in the estuaries and coastal
waters of Africa, but crossing the Atlantic to reach South America as
well.
* At their peak, the Gavialoidea were numerous and diverse; they
occupied much of Asia and America up until the Pliocene.
* One species, Rhamphosuchus crassidens of India, is believed to have
grown to an enormous 15 metres (~50 feet) or more.
* In India, small populations are present and increasing in the
rivers of the National Chambal Sanctuary, Katarniaghat Wildlife
Sanctuary, Son River Sanctuary and the rainforest biome of Mahanadi in
Satkosia Gorge Sanctuary, Orissa, where they apparently don’t breed
* In Nepal, small populations are present and slowly recovering in
tributaries of the Ganges, such as the Narayani-Rapti river system in
Chitwan National Park and the Karnali-Babai river system in Bardia
National Park
* They are extinct in Pakistan’s Indus River, in the Brahmaputra of
Bhutan and Bangladesh and in the Irrawaddy River in Myanmar.
* The average lifespan in the wild is 40 to 60 years, average size is
12.25 to 15.5 ft (3.6 to 4.5 m) and weight is 2,200 lbs (977 kg)
* Did you know that the gharial’s scientific name, Gavialis
gangeticus is based on a misspelling of the Hindi word ghariyal?
* The length of the snout is 3.5 (in adults) to 5.5 times (in young).
* There are nine protected areas for this species in India which are
linked to both captive breeding and ‘ranching’ operations where eggs
collected from the wild are raised in captivity (to reduce mortality due
to natural predators) and then released back into the wild (the first
being released in 1981).
* In the 1970s, the gharial came to the brink of extinction and even
now remains on the critically endangered list.
* More than 3000 animals have been released through these programmes,
and the wild population in India is estimated at around 1500 animals’
with perhaps between one and two hundred animals in the remainder of its
range.
* Gharial are grey/olive in colour with youngsters being paler. Their
tail is laterally flattened and they have broadly webbed feet which
enables them to be extremely agile and quick when in the water.
* Gharial are found in the slow moving backwaters of large rivers in
the northern Indian subcontinent. They spend most of their time in the
water, only leaving it to bask in the sun or to lay eggs.
* Gharials feed almost exclusively on fish although occasionally they
will feed on water birds or carrion. Young Gharials will eat insects,
larvae and small frogs. |
